This invention relates to bag forming machines of the top stacking type and is primarily concerned with such machines for forming bags from webs of thin (less than 0.025 mm) synthetic plastics material.
There is a natural inclination to design bag forming machines to operate on a continuous rhythmic basis throughout but there is inherently a limitation in that the formed bags are required to be stacked and removed in batches. In top stacking types of machines currently in use, the bag forming line is arrested whilst a stack of bags is removed and the stacking station re-set to begin re-stacking. Design solutions to the above limitation are restricted in that a stack of bags of thin synthetic plastics material are unstable. Individually bags are slippery and nearly air buoyant. They cannot be moved at high speed unsupported or accelerated or decelerated rapidly.